1. Field of the Invention
The present invention relates to an electric surgical operating apparatus which performs medical treatment to organism tissue and the like such as excision and coagulation, using high-frequency electric power.
2. Description of the Related Art
In recent years, electric surgical operating apparatuses which perform medical treatment to organism tissue and the like such as excision and coagulation by using high-frequency electric power have come to be known. Generally, such electric surgical operating apparatuses are configured having a high-frequency cauterization electric power source device for generating high-frequency electric current, and a high-frequency cauterization treating instrument provided with an active electrode for coming into contact with the area of the patient to be treated, and executing medical treatment with high-frequency electric current.
Regarding the types of the high-frequency cauterization treating instrument, monopolar treating instruments and bipolar treating instrument are known.
Monopolar treating instruments are configured having an active electrode which is connected to one output terminal of the high-frequency cauterization electric power source device and comes into contact with the area of the patient to be treated, and a feedback terminal portion which is connected to the other output terminal and is in plan contact with the body surface of the patient at a portion other than the area of the patient to be treated. The high-frequency cauterization electric power source device generates high-frequency electric power, this high-frequency electric power is concentratedly introduced into the organism tissue via the active electrode which is in contact with the area to be treated, and this high-frequency electric current is dispersed and recovered by the feedback electrode, thus enabling medical treatment to be performed on the organism tissue, such as excision, coagulation, and the like.
Conversely, bipolar treating instruments do not have a feedback electrode, with the line portion from which the active electrode extends being connected to both output terminals of the high-frequency cauterization electric power source device. There are various forms of the active electrode, according to use. For example, the is a loop-shaped loop electrode such as shown in FIG. 1A, a band-shaped band electrode such as shown in FIG. 1B, a roller-shaped roller electrode such as shown in FIG. 1C, and so forth.
Generally, once the supply of high-frequency electric power from the high-frequency cauterization electric power source device to the active electrode begins, heat is transferred to the organism tissue from the active electrode which has generated heat due to this high-frequency electric power. This generated heat causes transpiration of the organism tissue resulting in tissue degeneration, and as shown in FIG. 2, load impedance increases with time. Then, voltage drop owing to load impedance increases, and the output voltage of the electric surgical operation apparatus increases. When the output voltage reaches the predetermined voltage VE, arc discharge from the active electrode to the organism tissue is started. This arc discharge starts the excision operation on the organism tissue.
Incidentally, the reference symbols a, b, and c in FIG. 2 indicate that the properties of the active electrodes differ according to the electrode form, size, volume, material, and so forth. Also, in addition to the excision operation performed on the organism tissue, a coagulation operation can be performed, by modulating the waveform of the high-frequency current into a intermittent waveform, or lowering the output voltage in comparison with the voltage at the time of excision, thus facilitating hemostasis.
The output power of such an electric surgical operating apparatus exhibits properties such as shown in FIG. 3 as to the load impedance which is the impedance of the organism tissue.
That is, in the event that the load impedance is within a predetermined range from the rated load impedance, the rated output electric power necessary for performing the treatment to the area to be treated can be obtained, but in the event that the load impedance is smaller or greater than this range, the output voltage decreases, and output electric power necessary for performing the treatment to the area to be treated cannot be obtained.
Incidentally, the organism tissue prior to supply of high-frequency electric power to the active electrode normally contains a great deal of moisture, so the load impedance is small, and the rated output power cannot be obtained.
Also, the output power reaches the maximum value when the load impedance is near the predetermined rated load impedance value. The farther the load impedance value is from the rated load impedance, the smaller the output power is. Thus, the load impedance changes according to the state of the above-described tissue deterioration, consequently allowing the output power to change, so optimal output voltage for performing excision or coagulation cannot be obtained.
For example, in the event that the output voltage at the time of performing the excision operation is great, high-density discharge energy is transferred to the organism tissue when conducing the arc discharge. Conversely, in the event that the output voltage is small, there is no arc discharge. Consequently, trouble similar to that in excision occurs for performing coagulation as well, in the event that optimal output voltage for coagulation cannot be obtained. This means that the speed and so forth of tissue deterioration differs from that which the operator intends, due to optimal output voltage not being obtained.
Accordingly, means are provided in the First Embodiment of the high-frequency electric scalpel apparatus disclosed in Japanese Unexamined Utility Model Publication 4-30509 measures the output voltage value so that the stability of excision and coagulation operations can be improved by setting an appropriate target value, thereby comparing the output voltage value with the set target value and increasing or reducing the gain of the output circuit to maintain the output voltage value at the target value by performing constant-voltage control, whereby change in the output voltage is reduced as to change in the load impedance. Also, means for performing constant-voltage control and constant-power control are described in another embodiment disclosed in this Japanese Unexamined Utility Model Publication 4-30509, but these cannot be applied to the object of stabilizing the output voltage.
Also, with the electric surgical operation apparatus such as shown in FIG. 2, there is the problem of a delay in time occurring from the point of starting output of the electric power to the time of starting the excision or coagulation operation to the area to be treated. Also, increasing the output current in order to accelerate the deterioration of the organism tissue speeds up the increase of load impedance, but there has been a problem in that excessive power is output even after the load impedance reaches the necessary value.
Accordingly, the high-frequency electric scalpel apparatus in Japanese Patent No. 2542058 for example discloses means which enables control to be made such that the output current increases for a predetermined amount of time following starting of power output, wherein power with increased current is output during the period immediately following starting power output when the load impedance is small so as to accelerate tissue deterioration, following which appropriate power output can be made after a certain amount of time. This shortens the amount of delay in time from starting power output to the start of the excision/coagulation operation.
Further, the treating instrument of the above-described electric surgery operating apparatus is generally provided with an insulating covering at places other than the electrode. However, in the event that this insulating covering is damaged and insulation destruction occurs, this can cause trouble such as the insulation destruction portion coming into contact with the organism tissue causing the organism tissue to heat and deteriorate, decrease in voltage applied to the area to be treated, and so forth. Accordingly, with electric surgery operating apparatus, attention is paid to the voltage withstanding properties of the treating instrument when using.
The main unit of the electric surgery operating apparatus generally allows the output power level thereof to be adjusted, and the output voltage changes according to the setting state of this output power level. Thus conventionally, the output power level is adjusted while the technician takes care that the output voltage value does not exceed the maximum usage voltage value of the treating instrument, based on the maximum usage voltage value information provided in the operating manual of the treating instrument, and information of properties of the output voltage corresponding to the state of setting the output power levels as described in the operating manual of the electric surgery operating apparatus, which has been troublesome to the extent of being a problem.
In order to solve this problem, Japanese Examined Utility Model No. 8-5687 describes a means wherein, with a high-frequency electric scalpel apparatus arranged such that a special treating instrument having the function of telling the electric surgery operation apparatus the voltage withstanding value being connected to the main unit of the electric surgery operation apparatus, the maximum voltage value of high-frequency electric power which can be applied to the connected treating instrument is automatically recognized, and control is made so that the output voltage from the electric surgery operation apparatus does not exceed the maximum voltage value.
However, with generally-used electric surgery operation apparatuses, the output power can be adjusted, and such apparatuses are arranged such that the speed and the like of tissue deterioration can be adjusted by changing the output power. However, according to the means of the First Embodiment described in the aforementioned Japanese Unexamined Utility Model Publication No. 4-30509 setting the target value in order to adjust the output power results in the output voltage at the time of performing excision or coagulation changing, so appropriate output voltage cannot be obtained for the excision or coagulation; so the setting must be changed again to a target value during treatment in order to obtain output voltage appropriate for the excision or coagulation operation, meaning that there has been a problem in operability.
Also, in the event that the electrode form, size, volume, or material of the active electrode making up the high-frequency cauterization treating instrument differ as shown in FIGS. 1A through 1C, there is difference in the delay time to the start of the excision/coagulation operation as shown in FIG. 2. That is to say, the sense of operating the active electrode differs depending on the form, size, volume, or material thereof, so there has been the problem in unnaturalness in the operability.
Further, with the high-frequency electric scalpel apparatus in the above-mentioned Japanese Examined Utility Model No. 8-5687, the treating instrument connectable to the main unit of the electric surgery operation apparatus is restricted only to specialized ones having functions for telling the electric surgery operation apparatuses of the maximum voltage value, and thus not only was the range of selection of treating instruments limited, but also resulted in treating instruments being expensive. Moreover, though means are disclosed in the above high-frequency electric scalpel apparatus for preventing insulation destruction of the treating instrument, no means are described for detecting the insulation destruction occurring in the event that insulation destruction of the treating instrument actually does occur.
Accordingly, it is an object of the present invention to provide an electric surgical operating apparatus which performs medical treatment such as excision and coagulation operations in a stable and unintrusive manner, even in the event that the output electric power settings are changed.
It is another object of the present invention to provide an electric surgical operating apparatus which reduces the difference in delay in the time for starting operation which occurs due to different treating instruments having different electrode forms, sizes, volumes, and materials, thereby doing away with the unnaturalness in operating sense.
It is a further object of the present invention to provide an electric surgical operating apparatus which prevents voltage exceeding the voltage withstanding value of the treating instrument being applied thereto, thereby preventing insulation destruction of the treating instrument, without using special treating instruments.
It yet another object of the present invention to provide an electric surgical operating apparatus wherein occurrence of insulation destruction of the treating instrument or the danger thereof is detected, thereby avoiding or facilitating avoidance of problems occurring due to insulation destruction of the treating instrument.
Concisely, the electric surgical operation apparatus according to the present invention comprises:
an active electrode for performing medial treatment to an area to be treated by applying electric energy to the area;
an electric power supplying unit which supplies electric power to the active electrode;
a measuring unit which measures at least one of the electrical power output voltage value supplied to the active electrode from the electric power supplying unit, and the output current value thereof;
a discerning unit for discerning whether or not the change in at least one of the voltage value and the current value measured by the measuring unit has attained a predetermined change amount; and
a voltage control unit for controlling the electric power supplying unit so that the supplied electric power is a constant voltage, according to the discerning results discerned by the discerning unit.